They are taking their case to Alamance County parents, pointing out three schools—Sylvan Elementary in Snow Camp, Pleasant Grove Elementary in Burlington and B. Everett Jordan Elementary in the Saxapahaw area—sit within a half-mile of biosolid operations.

Some Alamance County schoolkids have become ill from sludge sprayed on nearby fields, parents and teachers said at a Burlington City Council meeting this month. Representatives for Alamance-Burlington Schools could not be reached for comment by press time Tuesday.

The clamor prompted Burlington leaders this month to halt biosolid application during school hours as city staff review the practice. Burlington counts roughly 4,000 acres permitted for application within municipal limits.

"They should be looking at a better way to dispose of it," says Sue Dayton, a Saxapahaw antique seller and, like Dotson, an environmental activist. "And they should tell the truth."

The truth about sludge, it seems, depends on whom you ask.

A survey published in March by UNC-Chapel Hill epidemiologists echoed Dayton's and Dotson's worries. More than half of the 34 sludge field neighbors interviewed in North Carolina, South Carolina and Virginia blamed the farming operations for health ailments—difficulty breathing, skin infections or sores, nausea and migraines.

The survey called for greater regulation and research, citing studies that indicate sludge treatment and applications are based on "outdated science and may be insufficient to protect public health and the environment."

Authors reported lax enforcement of biosolid regulations that depend on self-reporting, including accounts of sludge spills, runoff into waterways and cattle grazing on just-sprayed lands, despite regulations mandating a 30-day waiting period for grazing. University researchers also noted social justice issues because the majority of sludge applications are found in rural areas.

State maps confirm that finding. Permitted fields stretch across North Carolina—including Orange and Wake counties—but are heavily clustered in rural areas.

"Urban people are having the advantage of a cheap way to get rid of their waste," says report co-author Steve Wing. "But it's at the expense of the rural people."

But most environmental regulators and waste managers say biosolid use is safe. The N.C. Department of Environment and Natural Resources (DENR) and the U.S. Environmental Protection Agency (EPA) cite biosolid application as a "beneficial" reuse of waste. Without the land application, sludge byproduct would pile up at regional wastewater treatment plants, they say.

Additionally, proponents note scientific research, including the UNC survey, has failed to find a cause and effect relationship between biosolid application and reported negative impacts on health and the environment .

"One of the biggest problems for this product is misinformation," says Eric Davis, water and sewer operations manager for the City of Burlington.

Bob Rubin, N.C. State professor emeritus in biological and agricultural engineering, says he has researched and advocated for biosolid reuse for 40 years. Rubin says he would not advocate if he did not believe it to be safe.

"The detractors of our practices point to the unknowns and say, 'Well, you don't' know everything,'" Rubin says. "Well, you don't know what's in the food you eat, but you still eat it."

Nevertheless, UNC report co-authors Wing and Amy Lowman say the survey's results should not be ignored.

"Look at lead-based gasoline; look at asbestos," Wing says. "They were done for decades before people realized it was killing us or making us sick."

Local governments contract with companies to spread the treated waste byproduct in and outside of their borders. In most cases, the sludge is offered free to local farmers. Biosolids are broken down into Class A and Class B designations, with the former a higher-treatment option eliminating 99 percent of pathogens and bacteria.

The latter, according to DENR, is a less stringent—and more common—treatment alternative that reduces pathogen levels by 90 percent, meeting federal and state limits.

A 2010 DENR report estimated approximately 5,000 fields, or about 107,000 acres statewide, were permitted for Class B dispersal as of September 2009. Approximately 88,500 dry tons of the sludge was spread in North Carolina in 2008, the report says.

Former state lawmaker Joe Hackney, a powerful Democrat and longtime cattle farmer in Chatham County, says he has used biosolids for 20 years, but regularly tests soil samples and wells for contamination. "We have not perceived any problems from it," Hackney says.

John Kiviniemi, biosolids manager of Orange Water and Sewer Authority (OWASA), says his agency includes 1,000 acres in Orange, Chatham and Alamance in its biosolid recycling program, spreading about 700 dry tons a year over farmlands. He notes, however, that OWASA only spreads Class A sludge.

Local governments, as Orange Board of Commissioners Chairman Barry Jacobs points out, are mostly powerless to limit its dispersal. However, county leaders lobby for that power each year with state lawmakers.

"There's definitely something to be said for having an inexpensive, if not free, fertilizer source for farmers who are working with small margins of profit," Jacobs says. "But we're not even at the place where [local leaders] are at the table."

DENR and EPA regulate the operations, ordering setback requirements from dwellings, waterways and drinking wells. However, as critics note, no specific setbacks exist to offer enhanced buffering for schools.

But Kiviniemi says decades of scientific study indicate the practice is safe. "It is just as safe for the environment as if people were putting out commercial fertilizer," he says.

That may be, Jacobs says, but when there is scientific discord, leaders should show caution.

"It's a little bit like the thought that cell phones cause damage to your brain or living under power lines is bad for your health," Jacobs says. "There's evidence that at least makes one cautious. Until you know better, it's better to be cautious than to just act like there's no problem."